On 04/27/2010 05:31 PM, Sylvain Galineau wrote:
> Note: the WG has resolved to add box-shadow back to CSS3 Background& Borders [1] but as the
> editor's draft has not yet been updated, the following refers to the last document version for which
> it was defined [2].
>
> According to the spec:
>
> # The fourth length is a spread radius. Positive values cause the shadow to grow in all directions by the
> # specified radius. Negative values cause the shadow to shrink. The shadow should not change shape
> # when a spread radius is applied: sharp corners should remain sharp.
> ...
> Given that preserving the overall shape is desirable and that the number of alternatives to achieve it should
> be fairly small, is this something implementors are interested in defining interoperably as part of this edit ?
Ok, so here's what I've got so far:
| The fourth length is a spread radius. Positive values cause
| the shadow shape to expand in all directions by the specified
| radius. Negative values cause the shadow shape to contract. For
| corners with a zero border-radius, the corner remains sharp.
| Otherwise the spread radius outsets the edge of the shadow by
| the amount of the spread radius in the direction perpendicular
| to the shadow's edge. (Note that for inner shadows, expanding
| the shadow means shrinking the shadow's perimeter.) The UA may
| approximate the spread shape by outsetting (insetting, for inner
| shadows) the shadow's straight edges by the spread radius and
| increasing (decreasing, for inner shadows) and flooring at zero
| the corner radii by the same amount.
This preserves a strict geometrical definition of "spread", but allows
the UA to approximate it with an easy-to-draw shape. I kept the "leave
corners sharp" option, since it's probably useful, although I do not
have a strong opinion on it at this point.
What do people think?
~fantasai